1. Field of the Invention
The present invention relates to the transfer of fuel from a fuel tanker truck to an underground storage tank (UST) and the transfer of vapor from the UST to the tanker truck. In particular, the invention relates to attaching the hose from the tanker truck to the UST in such a manner that it does not loosen the fill pipe adapter or fill pipe (or the vapor pipe) on the UST. More specifically, the invention concerns either: 1) a rotatable, swivel drop elbow, which permits the drop elbow to rotate about the axis of the fill pipe or vapor pipe of the UST, or 2) a swivel adapter for use with a conventional fixed drop elbow, whereby the adapter rotates about the axis of the fill pipe or vapor pipe. Both devices do not transfer significant torque from the hose to the fill pipe adapter or the vapor pipe, thus insuring that the transfer of fuel occurs without leakage of vapor or liquid into the environment.
2. Prior Art
Conventional UST""s are filled by means of a fill pipe that projects upwardly from the tank and terminates with a fill pipe adapter, in a containment vessel designed to contain spilled fuel. The containment vessel has an opening covered by a manhole that provides access to the fill pipe and fill pipe adapter. The fill pipe adapter: 1) permits coupling with the drop elbow of a hose of a tanker truck thereby preventing any leakage into the environment, and; 2) prevents dirt and other bits of foreign matter from dropping into the UST through the fill pipe. Conventional UST""s also have a vapor pipe so that as the fuel is dropped into the UST, the displaced vapor is transferred to the tanker truck, replacing the volume of dropped fuel.
U.S. Pat. No. 5,535,984 to Anderson et al discloses a tanker truck having a hose terminating in a fixed drop elbow. The elbow has a quick connect type action that permits connection to the fill pipe adapter of a fill pipe of a UST. The spirit of this invention lies with securing the elbow securely to the fill pipe so that no fuel is spilled when filling the UST.
Frequently, a hose on the tanker truck is extracted from the truck in such a way that it is not straight and has one or more loops and kinks, causing axial forces to be applied to the fixed drop elbow especially when fuel flows through the hose causing it to stiffen and straighten. Should the drop elbow be connected to the fill pipe adapter without straightening the hose and removing all loops and kinks, the fixed drop elbow transfers those axial forces to the fill pipe adapter. Because the fill pipe and its fill pipe adapter are fastened to one another or to the UST by screw threads, with time the summation of these axial forces, in the counter direction of rotation of the screw threads, causes the fill pipe and/or fill pipe adapter to loosen and vapors to escape the UST. In sever cases, the fill pipe adapter and/or fill pipe may even detach from the UST. On the other hand, if the summation of the axial forces is in the direction of rotation of the screw threads, the gasket material can be crushed, fail and likewise lead to escaping vapors or fuel spills.
In view of the problem described above, there is a need for an improved system that overcomes the problems set forth above and yet maintains the quick connect features now present on conventional drop elbows. Advantageously, there is a need for a drop elbow that prevents any significant torque forces from being transmitted to the fill pipe adapter and/or fill pipe. Most expediently, there is a need for a drop elbow that is adaptable to existing equipment, such that every UST fill pipe and/or fill pipe adapter does not need to be modified to prevent torque forces from transferring to the fill pipe adapter and/or its fill pipe. While the problems set forth above are stated with respect to the drop elbow, the same problem may also be present with respect to the vapor recovery hose running between the UST and the tanker truck.
The present invention will be described primarily in terms of the drop or fill pipe connection, but it is equally applicable to the hose running between the UST and the tanker truck for the recovery of vapors. The present invention relates to a drop elbow adapted to fluidly connect with the conventional female coupler of a hose from a tanker truck, on one end, and the fill pipe adapter or vapor pipe adapter of an underground storage tank on the other end. The drop elbow is rotatable and swivels 360 degrees with respect to the fill pipe, while remaining fluidly connected, thereby accommodating any kinks and loops in the hose, and correspondingly minimizing any torque forces which may be transferred to the fill pipe adapter and/or fill pipe. Moreover, the elbow of the present invention maintains a quick connect feature such that coupling the hose (having the drop elbow thereon) with the fill pipe adapter is simple, quick, and fluidly secure. Thus the rotatable drop elbow of the present invention is designed to replace the fixed drop elbow conventionally known.
In the broadest sense, the present invention concerns a rotatable, swivel drop elbow comprising a housing and an elbow tube, whereby the elbow tube can rotate 360 degrees relative to the housing while remaining fluidly connected. Additionally, the elbow has a cam and groove adapter that accepts a conventional female coupler on a hose of a tanker truck. Alternatively, the elbow can be secured to the hose by any conventional means such as by a simple hose clamp. Lastly, the housing includes a latch bar or other similar mechanism that is mechanically connected with one or more locking cams that permit the cam housing to securely and quickly fasten to the male fill pipe adapter or the vapor pipe of a UST.
The present invention also relates to the use of a swivel adapter-coupler for use with a conventional fixed drop elbow. The adapter-coupler is positioned between the non-rotatable, fixed drop elbow and the conventional fill pipe adapter. This swivel adapter-coupler converts the fixed drop elbow into a rotatable drop elbow while remaining fluidly connected.
In the broadest sense, the present invention also concerns a swivel adapter-coupler capable of rotating 360 degrees, comprising an adapter that accepts a conventional female coupler of a fixed drop elbow, and a coupler that securely and quickly couples to the male pipe adapter of a UST, while remaining fluidly connected.